This is a really interesting and insightful thread. I think the point Jen and Chrissy are making is a good one-- and subtle. On another thread someone talked about how HD/LD becomes part of your definition of yourself. I think over the years, as Real Life intrudes, there are other things that at one time were part of our definition of ourselves-- maybe even a cherished part-- and they get shoved aside because there aren't enough hours in the day to keep all the parts of us fed and maintained.
Jen and Chrissy have expressed very well the way that the stuff you have to do every day to maintain a life can cause sex to get edged out.
But think of the other stuff that gets edged out, too-- stuff that you've let go of and probably haven't noticed because it doesn't affect your partner, so there's no one to remind you.
In our younger days (pre-responsibility), maybe we played the piano or sang, or played sports, loved to go to foreign movies or art galleries, maybe painted or wrote poetry. If someone asked us, "Tell me about yourself," maybe we said, "Well, I love to take long bike rides, I paint a little, I'm almost fluent in French," (and then we think, but don't say out loud: "I keep in shape, I know I'm attractive, and I'm GREAT in the sack!").
Over the years, responsibilities take over and the married/parent self starts to push out the other aspects of our self-definition. Don't get me wrong-- I think people welcome it. They love parenthood and they love their kids. But sometimes there isn't enough emotional energy to be everything we once thought we would/could be.
I don't know about y'all, but I remember looking at the older generation and saying to myself, "Well, that will never happen to me!" Meaning I would never lose my drive, optimism, idealism, and I would always be able to keep a strong sense of that Girl inside who at one time thought anything was possible. (And I'm part of the generation that had as its motto: "Don't trust anyone over 30!" )
Anyway, I wanted to validate what Jen and Chrissy were saying-- that it's not a case of deciding consciously that laundry is more important than sex, but that as we become immersed in adult life, there are other aspects of our younger, free-from-responsibility selves that we let go of, and no one notices. We dust the piano and remember the musical aspirations we once had. Or see the sports trophies from college on the mantle and laugh when we remember how we once thought that would become a career.
I'm not saying this is right-- just that it's understandable. In the case of sex, it is one way to stay in touch with that vibrant, passionate, adolescent who thought all things were possible. But first we have to become aware that we have let him/her slip away.
As Chrissy said, when the kids are gone, some couples reconnect and rediscover those more carefree emotional times. Ideally, that's what would happen, along with taking up the piano and painbrush again. But I think the connection with your partner sexually has to be maintained in some way or you won't be able to get back there.